1. Field of the Invention
The present invention relates to a connector for a coaxial cable and particularly to the connector which electrically connects a plug with a receptacle and has a switch operable in response to insertion or removal of the plug into or from the receptacle.
2. Description of the Related Art
The coaxial cable connector has long been well known comprising a plug and a receptacle, an example of which is shown in FIGS. 7A and 7B in a schematic longitudinal section representation. Particularly, FIG. 7A shows the conventional coaxial cable connector without the plug having not yet been inserted, and FIG. 7B shows the same coaxial connector with the plug having been inserted.
Referring to these figures, the connector 1 for a coaxial cable has a body 10, which is molded of, for example, synthetic resin. The body 10 has a recess 11 defined therein so as to extend inwardly from one end thereof, and also has a tubular body 12 protruding a distance from the bottom of the recess so as to face the opening of the recess 11. The tubular body 12 has a housing space 13 defined therein. A normally closed switch 5 is accommodated in the tubular body 12. The switch 5 includes a displaceable terminal 3 and a stationary terminal 4, both of which are made of an electroconductive material. The tubular body 12 is provided with a ground terminal 6 encircling an outer surface thereof. A receptacle 2 consists of the tubular body 12, the switch 5 and the ground terminal 6. The receptacle 12 is adapted to removably receive therein a plug 7 coupled with the coaxial cable. The tubular body 12 has an aperture 14 defined on one end thereof within the recess 11 and communicating the housing space 13 with the recess 11 therethrough. An inner peripheral edge of the tubular body 12 around the aperture 14 is inwardly tapered at 15 to facilitate insertion of a center contact 7a of the plug 7 into the aperture 14.
The stationary terminal 4 is disposed within the housing space 13 and fixedly held against an inner wall of the tubular body 12 defining the housing space 13 so as to face the displaceable terminal 3. The displaceable terminal 3 has a base portion 37 fixedly held against the inner wall of the tubular body 12 defining the housing space 13 at a location opposite to the position of the stationary terminal 4 with an end portion 38 of the displaceable terminal 3 disposed within the housing space 13 so as to face the aperture 14. The displaceable terminal 3 is urged toward the stationary terminal 4 by its own resiliency. Therefore, as shown in FIG. 7A, a contact portion 39 of the displaceable terminal 3 that is situated between the end portion 38 and the base portion 37 is held in contact with stationary terminal 4 thereby to keep the switch 5 closed when the plug 7 is not connected to the receptacle 2. On the other hand, as shown in FIG. 7B, when the plug 7 is connected to the receptacle 2 with the center contact 7a inserted into the housing space 13 through the aperture 14, the center contact 7a is brought into sliding contact with the end portion 38 causing the end portion 38 to separate away from the stationary terminal 4. In this condition of FIG. 7B, not only is the center contact 7a of the plug 7 connected electrically with the displaceable terminal 3, but the normally closed switch 5 is opened.
Also, the center contact 7a urges the end portion 38 that is further from base portion 37 than the contact portion 39, so long as the plug 7 is connected to the receptacle 2. Therefore, the distance of travel of the end portion 38 is small. As a result, a contact gap G between the displaceable terminal 3 and the stationary terminal 4 is so small that an insulation characteristic would likely become worse. Also, the connector 1 for the coaxial cable could not be made compact. Further, if the accuracy with which parts such as the displaceable terminal 3 or the stationary terminal 4 are machined insufficiently, the switch 5 will fail to operate properly.
Also, where the connector is downsized, the size of the taper 15 becomes too small and is likely to fail to guide the center contact 7a inserted through the aperture 14. Also, as the end portion 38 is repeatedly depressed by the center contact 7a, then the displaceable terminal 3 is likely to be set in a buckled state. Therefore, it is difficult to downsize the connector.